This invention relates to mixers for liquids and solids in a tank, and more particularly to the art of planetary type mixers.
The mixers under discussion here are of those type suited to a wide range of liquid and solid mixing applications, from simple mixtures to sophisticated reactions involving high temperature, vacuum, or internal pressure.
One type of mixer in common use is the multiple agitator mixer, which has several types of agitators that can operate simultaneously or independently in a single can, or tank, so that a selected combination of agitations covering a range of low to high viscosity consistencies can be applied when two or more compounds each having substantially different viscosities are being mixed. Each agitator rotates about its own axis and an anchor agitator rotates within the tank about a central axis. Two or three agitators used in a single mixer can include two or three of the following: a high speed mixer-emulsifier, a high speed disperser, or a standard anchor agitator used in selected combinations. Applications are extensive in the adhesives, cosmetics, chemical, food, pharmaceutical and plastics industries. Tank sizes range between 1 gallon to 4000 gallons. Rotational agitator tip speeds range approximately between 2500 FPM to 5000 FPM for a disperser, 2500 FPM to 5000 FPM for an emulsifier, and 150 FPM to 450 FPM for an agitator. Each shaft is driven by a separate driver and a separate gear box for varying speeds of each drive shaft. This type of mixer is described in a brochure entitled "VersaMix" published by Charles Ross & Son Company, 710 Old Willets Path, Box 12308, Hauppauge, New York 11788-0615.
Another type of mixer in common use is the double planetary mixer having two stirrer blades. During the mixing cycle, two rectangularly shaped stirrer blades revolve about the tank on a central axis. Simultaneously, each blade revolves on its own axis at approximately the speed of the central rotation. The double planetary mixer is used for a wide range of liquid and solid mixing applications, including plastisols, bulk molding compounds, pharmaceutical granulations, ceramics, caulking compounds, composites, magnetic coatings, precious metals, and dental composites. Two planetary stirrers are used. This type of mixer is used in both laboratory and production mixers. It is often used in vacuum applications. Can size ranges between 1 quart and 500 gallons. Planetary blade speeds range approximately between 10 rpm to 100 rpm. This type of mixer has one shaft driven by one driver and has one gear box for varying speed. The rotational speed of each planetary stirrer blade is the same. This type of mixer is described in a brochure entitled "Double Planetary Mixers" published by Charles Ross & Son Company, 710 Old Willets Path, Box 12308, Hauppauge, New York 11788-0615.
Problem with each of the described mixing systems exist. These problems are basically three. First, the multi-agitator mixing system and the mixing tank must be dimensioned to fit one another. Second, a separate driver is needed for each shaft in the multi-agitator system. Third, the planetary mixer system uses two identical stirrers that must rotate at the same speed.